We are told that the first part of the process is to select the very smallest seeds from the smallest plants, which is not at all unlikely, but I cannot speak to the fact from my own observation.
Robert FortuneThe Chinese, by their favourite system of dwarfing, contrive to make it, when only a foot and a half or two feet high, have all the characters of an aged cedar of Lebanon.
Robert FortuneSometimes, as is the case of peach and plum trees, which are often dwarfed, the plants are thrown into a flowering states, and then, as they flower freely year after year, they have little inclination to make vigorous growth.
Robert Fortune